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Concept

Phonon

Publications associées (30)

Large impact of phonon lineshapes on the superconductivity of solid hydrogen

Lorenzo Monacelli

Phonon anharmonicity plays a crucial role in determining the stability and vibrational properties of high-pressure hydrides. Furthermore, strong anharmonicity can render phonon quasiparticle picture obsolete questioning standard approaches for modeling sup ...

Nature Portfolio2024

Phonons, electron-phonon coupling and charge transport in low-dimensional materials

Norma Rivano

Over the past few decades, nanostructures have garnered significant attention due to their potential for embodying new physical paradigms and delivering cutting-edge technological applications. Dimensionality strongly affects the vibrational, electron-phon ...

EPFL2023

Wigner Gaussian dynamics: Simulating the anharmonic and quantum ionic motion

Lorenzo Monacelli

The atomic motion controls important properties of materials, such as thermal transport, phase transitions, and vibrational spectra. However, simulating the ionic dynamics is exceptionally challenging when quantum fluctuations are relevant (e.g., at low te ...

AMER PHYSICAL SOC2023

Infrared-active phonons in one-dimensional materials and their spectroscopic signatures

Nicola Marzari, Thibault Daniel Pierre Sohier, Norma Rivano

Dimensionality provides a clear fingerprint on the dispersion of infrared-active, polar-optical phonons. For these phonons, the local dipoles parametrized by the Born effective charges drive the LO-TO splitting of bulk materials; this splitting actually br ...

Nature Portfolio2023

Electron-phonon driven unconventional superconductivity: The role of small Fermi energies and of nonadiabatic processes

Claudio Grimaldi

The very concept of high-T-c superconductivity has originated from the discovery of superconductivity in copper oxides by Bednorz and Muller in 1986. Soon after their discovery, cuprates were recognized as undoubtedly complex and radically unconventional s ...

Elsevier2023

Imaging and controlling coherent phonon wave packets in single graphene nanoribbons

Klaus Kern

The motion of atoms is at the heart of any chemical or structural transformation in molecules and materials. Upon activation of this motion by an external source, several (usually many) vibrational modes can be coherently coupled, thus facilitating the che ...

Nature Portfolio2023

Long-range electrostatic contribution to electron-phonon couplings and mobilities of two-dimensional and bulk materials

Nicola Marzari, Marco Gibertini, Samuel Poncé, Massimiliano Stengel

Charge transport plays a crucial role in manifold potential applications of two-dimensional materials, in-cluding field-effect transistors, solar cells, and transparent conductors. At most operating temperatures, charge transport is hindered by scattering ...

AMER PHYSICAL SOC2023

Identifying Large Charge operators

Riccardo Rattazzi, Alexander Monin, Gil Badel

The Large Charge sector of Conformal Field Theory (CFT) can generically be described through a semiclassical expansion around a superfluid background. In this work, focussing on U(1) invariant Wilson-Fisher fixed points, we study the spectrum of spinning l ...

Springer Nature2023

Interfacial Inversion, Interference, and IR Absorption in Vibrational Sum Frequency Scattering Experiments

Lei Zhang, Sylvie Roke, Saranya Pullanchery Sankara Narayanan, Sergey Kulik

Molecular interfacial structure greatly determines thepropertiesof nano- and microscale systems. Vibrational sum frequency scattering(SFS) spectroscopy is a unique interface-selective tool to measurethe interfacial vibrational spectrum of sub-micron to mic ...

AMER CHEMICAL SOC2023

Correlated insulator collapse due to quantum avalanche via in-gap ladder states

Xi Chen, Camille Didier Georges Aron

The significant discrepancy observed between the predicted and experimental switching fields in correlated insulators under a DC electric field far-from-equilibrium necessitates a reevaluation of current microscopic understanding. Here we show that an elec ...

Nature Portfolio2023

Direct Observation of the Phase Transition in C60 Fullerene

Chengcheng Yan

In the third study, the order-disorder phase transition of single-crystal C60 is studied using time-resolved electron microscopy. Solid C60 undergoes a first-order phase transition upon heating to 260 K. This is a structural transition from the low-tempera ...

EPFL Infoscience2023

Observation of non-reciprocal harmonic conversion in real sounds

Romain Christophe Rémy Fleury, Hervé Lissek, Xinxin Guo

Reciprocity guarantees that in most media, sound transmission is symmetric between two points of space when the location of the source and receiver are interchanged. This fundamental law can be broken in non-linear media, often at the cost of detrimental i ...

2023

Self-injection Locked Second-Harmonic Generation in Optically Poled Silicon Nitride Microresonators

Tobias Kippenberg, Camille Sophie Brès, Junqiu Liu, Edgars Nitiss, Marco Clementi

We present a narrow-linewidth second-harmonic source based on a laser diode injection locked to an optically poled silicon nitride microresonator. The device is a compact, highly-coherent dual-wavelength source, with high conversion efficiency up to 280%/W ...

2023

Wigner Formulation of Thermal Transport in Solids

Nicola Marzari, Michele Simoncelli

Two different heat-transport mechanisms are discussed in solids. In crystals, heat carriers propagate and scatter particlelike as described by Peierls's formulation of the Boltzmann transport equation for phonon wave packets. In glasses, instead, carriers ...

American Physical Society2022

Optical spectroscopy of earth-abundant zinc pnictides for photovoltaics

Elias Zsolt Stutz

Zinc phosphide (Zn3P2) is an earth-abundant semiconductor with promising properties for applications as an absorber in photovoltaics. To beat the 40 years old record power conversion efficiency of solar cells made with this material, a deep understanding o ...

EPFL2022

General invariance and equilibrium conditions for lattice dynamics in 1D, 2D, and 3D materials

Nicola Marzari, Samuel Poncé, Changpeng Lin

The long-wavelength behavior of vibrational modes plays a central role in carrier transport, phonon-assisted optical properties, superconductivity, and thermomechanical and thermoelectric properties of materials. Here, we present general invariance and equ ...

NATURE PORTFOLIO2022

Ultrafast photo-induced phonon hardening due to Pauli blocking in MAPbI(3) single-crystal and polycrystalline perovskites

Samuel Poncé, Feliciano Giustino

Metal-halide perovskite semiconductors have attracted intense interest over the past decade, particularly for applications in photovoltaics. Low-energy optical phonons combined with significant crystal anharmonicity play an important role in charge-carrier ...

IOP PUBLISHING LTD2021

Evidence of a coupled electron-phonon liquid in NbGe2

Philip Johannes Walter Moll, Matthias Carsten Putzke, Mathieu François Padlewski

Whereas electron-phonon scattering relaxes the electron's momentum in metals, a perpetual exchange of momentum between phonons and electrons may conserve total momentum and lead to a coupled electron-phonon liquid. Such a phase of matter could be a platfor ...

Nature Portfolio2021

Non-classical photon-phonon correlations at room temperature

Santiago Tarrago Velez

With the development of quantum optics, photon correlations acquired a prominent role as a tool to test our understanding of physics, and played a key role in verifying the validity of quantum mechanics. The spatial and temporal correlations in a light fie ...

EPFL2021

Evidence for a spin acoustic surface plasmon from inelastic atom scattering

Davide Campi

Closed-shell atoms scattered from a metal surface exchange energy and momentum with surface phonons mostly via the interposed surface valence electrons, i.e., via the creation of virtual electron-hole pairs. The latter can then decay into surface phonons v ...

Nature Research2021